The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 02, 2014
Filed:
Apr. 11, 2011
Yilu Zhang, Northville, MI (US);
Siwei Cheng, Atlanta, GA (US);
Mutasim A. Salman, Rochester Hills, MI (US);
Yilu Zhang, Northville, MI (US);
Siwei Cheng, Atlanta, GA (US);
Mutasim A. Salman, Rochester Hills, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
A system and method for determining the speed of an alternator, for example, a vehicle alternator. The method includes measuring the current or voltage of a vehicle battery for a predetermined period of time, and then notch filtering the measured current or voltage signal to remove known harmonics. A limited data point Fast Fourier Transform (FFT) spectrum analysis operation is performed to identify the frequency peaks in the filtered signal, where the highest peak represents a ripple current on the DC alternator signal. The highest peak in the FFT signal is identified, and an interpolation process is performed between that peak and an adjacent peak in the data to identify the actual frequency of the ripple current. The ripple current is then converted to the speed of the alternator.